ORGANIC CHEMISTRY need help please?

[spidey2007]

wat is the diffrence between acetal and hemiacetal and also please tell me the mechanism of their formation reactions???

i also wanted to know wat is the product formed (IUPAC NAME OR COMMON NAME any one will do)
when C2H4O reacts indivisually with NH2OH and withNaHSO3???

[shoonutz]

Acetals are formed by reaction of either ketones or aldehydes with 2 equivalents of an alcohol and an acid catalyst(HCL). The formula for an acetal is R2C(OR')2. A hemiacetal is formed by nucleophilic addition of an alcohol to the carbonyl group of an aldehyde or a ketone. Hemiacetal formation is reversible, although equilibrium will favor the carbonyl (C=O) containing compound. In the presence of an acid catalyst, the reaction proceeds with protonation of the hemiacetal hydroxyl, which converts it into a leaving group. The reaction proceeds further resulting in the neutral acetal product. So the difference between the two as you have asked is hemiacetals are formed initially by reaction of ketones or aldehydes with alcohol. In the presence of an acid catalyst, the reaction proceeds further to yield the acetal product.

CH3CH=O, ethanal or acetaldehyde. It reacts with NH2OH(hydroxyl amine) to form CH3CH=NOH(acetaldehyde oxime).

CH3CH=O, ethanal or acetaldehyde. It reacts with NaHSO3(sodium bisulfite) to yield a bisulfite adduct CH3COHSO3Na(acetaldehyde sodium bisulfite).

Hope this helps.